IPwatchD is a simple daemon that analyses all incoming ARP packets in order to detect IP conflicts on Linux. It is released under the terms of the GNU General Public License version 2.

IPwatchD can be configured to listen on one or more interfaces (alias interfaces are also supported) in active or passive mode. In active mode it protects your host before IP takeover by answering Gratuitous ARP requests received from conflicting system. In passive mode it just records information about conflict through standard syslog interface.

IPwatchD also supports execution of user-defined scripts that can for example show bubble notification on user's desktop.